1. Field of the Invention
This invention relates to a microorganism culture apparatus, more particularly to the microorganism culture apparatus and method for conducting air exchange between inside and outside of the container in an aseptic environment. This invention is useful in the expansion culture of microorganisms, especially in the expansion culture conducted for test tube microorganisms.
2. Description of the Related Art
For the microorganism culture and especially the expansion culture conducted for test tube microorganisms, mechanical shakers are widely used. Currently, shakers in use domestically and abroad vary in model and type, including DXY single-shaft rotary shaker and CXY-2 reciprocating shaker (designed and supervised by Shanghai Industrial Microbiology Institute and manufactured by Chaoqiao Light Industry Machinery Factory in Wuxi Jiangsu); Model 4520 shaker produced by Forma Scientific Co. USA. Whichever model it is, the operation procedure is basically the same: place on an operation table multiple glass flasks that contains liquid culture medium already vaccinated, turn on the power, and let the shaker shake in a certain vibration frequency till the end of the microorganism growth period. Therefore, the main working principle involved is to enable the vibration of the liquid surface of the culture medium, allowing the air to enter into the flasks and provide for the microorganism growth. However, due to such a working principle, some disadvantages prevail in current shakers, regardless of the original producer:
1) Because the entire operation desk shakes, energy consumption is generally big, about 1 KVA for the entire machine;
2) Long-time mechanical vibration is inclined to cause mechanical failure;
3) Long-time mechanical abrasion generates noise and pollutes the environment;
4) Shaking rate limits the liquid allowed in the flask, usually covering only 20% of the total volume;
5) Composition variability is poor. Even when an experiment requires only one or two flasks of microorganism, the entire machine shall be operated, thus wasting energy;
6) Mechanical maintenance is difficult.
An USSR patent No. SU-808114 issued on Aug. 2, 1976 discloses a mixer for mixing solids and gases in culture liquids. However, this document does not mention how the air exchange is proceeded between the mixer and the outside environment.
A Japanese patent published on Sep. 20, 1994 (Publication No.6-261747) discloses a liquid culture apparatus and method that utilizes electro-magnetic agitation. In this application, a winged magnetic impeller flows on the free surface of the culture liquid in the container by virtue of buoyant force. The impeller is driven to rotate through the rotation of an external magnetic force at the bottom of the container. As a result, circulation of the culture liquid in the container is achieved, resulting in normal culture of biological cells. Nevertheless, no details concerning air exchange are discussed in this publication.
A U.S. Pat. No. 5,470,152 issued on Nov. 28, 1995 discloses an agitation tank characterized by a magnetically coupled mixer. The mixer includes a drive magnet that is connected to an electric motor and a driven magnet whose lower portion is fastened to an impeller. Both magnets are magnetically coupled so that one cycle of rotation in the drive magnet results in exactly one cycle of rotation in the driven magnet and the impeller. The drive magnet is driven to rotate by the electric motor, resulting ultimately in the rotation of the impeller and the circulation of the culture liquid in the tank. However, this patent does not mention the path for controlling the input and output of air, especially hydrogen.
Considering these, the objective of this invention is to provide an air exchanger inserting into the container, thus achieving an aseptic air exchange between inside and outside of the container in a more energy-efficient way.
The first aspect of this invention provides a magnetically coupled microorganism culture apparatus which includes: a container for holding microorganism culture medium liquid, said container having one or a plurality of gas outlets (8) and an opening (21) at its top, each said outlet having an air filtering film; a sealed filtering cap fastened at the top the container and covering said opening (21), the sealed cap having an inlet which is covered by an air filtering film; a hollow air sucker in the sealed cap, which is rotatable relative to the sealed cap and the flask, passing downward through said opening and then entering into the container; a hollow air impeller fastened to lower end of the sucker, being in a gaseous communication with the sucker; a driven magnet fastened to upper end of the sucker; a resisting structure fastened to the container near the impeller, for preventing the liquid in the container from generating eddy flow; wherein when said apparatus is applied to rotary magnetic field, the driven magnet brings the sucker and impeller to rotate along with it, thus sucking filtered air which enters into the sucker via the inlet into the liquid by centrifugal force so as to achieve the objective of air exchange.
The second aspect of this invention is to provide a microorganism culture apparatus, which includes: a container for holding culture medium liquid, having one or a plurality of gas outlets and an opening at its top, each said outlet being covered by an air filtering film; an air-purifying chamber, on the wall of which are one or a plurality of inlets covered by air filtering films; a hollow air sucker in the air-purifying chamber, entering the container through the opening, upper end of the sucker being fastened to the drive shaft of a micro motor via a coupling, the sucker having an air filtering film at its upper opening; a hollow air impeller fastened to the lower end of the sucker, said impeller being in a gaseous communication with said sucker; a resisting structure fastened to the container near the impeller, for preventing the liquid in the container from generating eddy flow; other than the gas sucker, there is almost no path to the container from the air-purifying chamber; when the micro motor is on, it drives the sucker and impeller to rotate, thus, sucking the filtered air which enters into the sucker via the inlet into the liquid by the centrifugal force and achieving the goal of air exchange between the inside and outside of the container.
The third aspect of this invention is to provide a method for conducting aseptic air exchange for the microorganism in a container by using magnetically coupled rotary means, said container including a container body for holding microorganism culture medium liquid, the container body comprising: one or a plurality of outlets (8) and an opening (21) at its top, each said outlet being covered by an air filtering film; a resisting structure located at the bottom of and fixed relative to the container for preventing the liquid in the container from generating eddy flow; said magnetically coupled rotary means comprising: a sealed filtering cap, on said cap is disposed with an inlet covered by an air filtering film; a hollow sucker placed through the sealed cap and being rotatable relative to the sealed cap; an impeller fixed at the lower end of the sucker, said impeller being in a gaseous communication with the sucker; a driven magnet fastened to the upper end of the sucker; said method including the following steps: lowering the sucker together with the impeller through the sealed cap into the container so that the impeller is at the same level as said resisting structure; fastening the filtering sealed cap onto the container opening, so that air flow between the sealed cap and the container is only allowed through the sucker; applying rotary magnetic field to the driven magnet; the driven magnet bringing the sucker and further the impeller to rotate; the filtered air which enters into the sucker via the inlet is sucked into the liquid by the centrifugal force so as to achieve an air exchange.
The fourth aspect of this invention is to provide a microorganism culture system using the above culture apparatus, which includes a box body, an adjustable DC power, a plurality of microorganism culture apparatuses placed in the box body and a corresponding number of time relays, wherein each culture apparatus is one according to the first or second aspect of this invention respectively; said plurality of culture apparatuses are divided into said number of groups, with the micro motors of each group are controlled by time relays with different duty cycles so that different amount of oxygen may be delivered to different groups of culture apparatuses, thereby achieving the object of cultivating different microorganisms in one box at the same time.
This invention is different from various currently used shakers in working principle. It has following advantages: (1) saving energy; (2) being free of mechanical vibration so that mechanical fault and noise are greatly decreased; (3) the amount of filling culture liquid for each microorganism culture apparatus is increased; (4) various microorganism culture apparatus can be used individually or be easily combined, so that energy is saved when single apparatus is used to conduct microorganism culturing; (5) simple and convenient operation, easy maintenance.